首先，找到你的socket文件:

First, to find your socket file:

mysqladmin variables | grep socket

对我来说，这给:

| socket                                            | /tmp/mysql.sock                                                                                                        |

然后，在您的 config/database.yml 中添加一行:

Then, add a line to your config/database.yml:

development:
  adapter: mysql2
  host: localhost
  username: root
  password: xxxx
  database: xxxx
  socket: /tmp/mysql.sock